Immunology - extra

Question 1

What is the time difference between activation of innate and adaptive immunity?

Answer 1

Innate is immediate. Adaptive takes 4-7 days to set in.

Question 2

How does manning-binding lectin work?

Answer 2

Binds to mannose sugar molecules although these are quite rare in mammals.

Question 3

What five substrates are involved in innate immunity?

Answer 3

• Interferons
• Interleukin 1 (fever symptoms)
• Mannin-binding lectin
• C-reactive protein
• Serum amyloid protein

Question 4

How do c-reactive protein and serum amyloid proteins work?

Answer 4

Bind to the molecules found in the cell walls in bacteria and fungi.

Question 5

What is clonal selection?

Answer 5

Where the relevant lymphocyte is activated by the foreign antigen and undergoes proliferation in order to fight off the specific pathogen.

Question 6

What undergoes recombination in B and T cells?

Answer 6

B - immunoglobin gene segments

T - TCR gene segments

Question 7

What differs in T lymphocytes in the young and the elderly?

Answer 7

Same number of T cells but less diversity when older - become oligoclonal.

Question 8

How does the thymus change during an infection?

Answer 8

No apparent change

Question 9

Where is Peyer’s patch found?

Answer 9

Lining of the gut (mainly B cells found here in the germinal centre)

Question 10

What is another name for the dendritic cells found in the skin/mucosa?

Answer 10

Epidermal langerhaans cells

Question 11

What is the function of the spleen and basic structure?

Answer 11

Filters the blood for antigens.

- The white pulp is directly next to the blood vessels perfused the organ, which is where the lymphocytes are found.

Question 12

What is the implication of having no spleen?

Answer 12

Immunocompromised, especially with encapsulated pathogens. People with their spleen removed must be vaccinated against these pathogens.

Question 13

How is a lymph node structured?

Answer 13

• Highly organised with different areas for B and T cells
• B cells aggregate towards the edge in follicles and form germinal centres in ongoing infections (this is what causes the lymph nodes to swell when you are ill)
• T cells are found slightly further towards the centre of the lymph node

Question 14

How are the CD3 polypeptides helpful on T cells?

Answer 14

Have longer cytoplasmic tails than the two protein chains expressed by the TCR so they are important in delivering the signal to the T cell when the correct antigen is encountered.
- Have tyrosine residues that are phosphorylated upon encountering the antigen.

Question 15

Where do T cells recognise antigens?

Answer 15

In secondary lymphoid organs.

Question 16

Where are dendritic cells found?

Answer 16

Widely distributed but mainly found in skin and mucosa.

Question 17

Where are macrophages and B cells found?

Answer 17

Lymphoid tissue

Question 18

What is diapedesis?

Answer 18

Movement of a cell across the endothelial layer.

Question 19

Other than epidermal langerhaans and intraepidermal lymphocytes, what other cells are helpful in detecting infection in the skin?

Answer 19

Keratinocytes - good at recognising damage int he skin and can secrete signalling molecules to communicate this.

Question 20

How is a neutrophil distinguished?

Answer 20

Multi-lobed nucleus

Question 21

How is a eosinophil distinguished?

Answer 21

Bi-lobed nucleus

Question 22

How is a basophil distinguished?

Answer 22

Bi-lobed nucleus

Question 23

What are neutrophil extracellular traps and when are they used?

Answer 23

When neutrophils are heavily activated they release granules proteins and nets that trap extracellular bacteria and immobilise them.

Question 24

What is the structure of the constant region of an antibody?

Answer 24

Barrel-shaped beta pleated sheet held together by highly conserved disulphide bridges.

Question 25

What is somatic hypermutation?

Answer 25

AID - activation induced deamination.
Causes minor point mutations so that the C in GC is changed to A so T is found on the template strand. These result in slight changes in the antibody over time.

Question 26

How do the Class I and II MHC molecules differ in structure?

Answer 26

• MHC I only have one transmembrane tail whereas MHC II has two
• MHC I has three alpha domains and one beta domain which is a microglobulin (same in everyone)
• MHC II have two alpha domains and two beta domains
• Alpha and beta domains are held together by non-covalent bonds in both MHC molecules

Question 27

Where is the HLA gene found?

Answer 27

Chromosome 6

Question 28

Which MHC class presents longer peptides?

Answer 28

MHC II

Question 29

What are toll-like receptors?

Answer 29

Class of transmembrane pattern recognition receptors (PRRs) that sense invading pathogens or endogenous damage signals. Able to initiate innate and adaptive immune responses.
- 10 found in humans
3,7,8,9 - recognise foreign nucleic acids
1,2,4,5,6,10 - recognise microbial constituents